Clamp for electric conductors



(No Model.)

A. H. ENGLUND. CLAMP FOR ELECTRIC GONDUGTORS.

Patented June 6 1893..

Unrrsn STATES PATENT Grates.

AXEL HELMER ENGLUND, OF CHICAGO, ILLINOIS.

CLAMP FOR ELECTRIC CONDUCTORS.

SPECIFICATION forming part of Letters Patent No. 498,776, dated June 6, 1893.

Application filed June 29. 1891. Serial No. 397,862. (No model.)

T0 to whmn it may concern.-

Beitknown that I, AXEL IIELMER ENGLUND, of Chicago, in the county of (look and State of Illinois, have invented certain new and useful Improvements in lVire-Supporting Clamps; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to wire supporting clamps, being designed more particularly for use in supporting trolley-line wires for electric railways, although obviously adapted for use in other connections, and has for its object to remedy certain defects which are found to exist in clamps of this character as ordinarily constructed. These clamps are usually and preferably constructed of brass or other alloys of copper, and being of considerable length, with the clamping force applied to the central portion only, the end portions, owing to their distance from the point at which the clamping force is applied and to the comparative weakness of the alloy of which they are constructed, are apt to become separated by the downward strain of the wire, and when the said end portions have separated to an extent su'flicient to permit the passage between them of a portion of the wire, the clamping devices can no longer withstand the wedging action of the wire which results, and the wire tears itself free from the clamps. In order to overcome this defect, these clamps have been constructed of steel or some other metal stronger than the alloy usually employed. This construction is objectionable for the reason that as the trolley-Wheel passes from the copper line-wireto the steel clamp, sparkin g occurs. To remedy the defect in strength just pointed out without incurring the dangers and disadvantages of this sparking is the object of my present invention, and to this end the said invention consists in certain novel features which I will now proceed to describe, and will then particularly point out in the appended claims.

In the accompanying drawings: Figure 1 represents a perspective view of a construction embodying my invention in one form. Fig. 2 is an elevation of one half of the clamp,

showing the inner face thereof. Fig. 3 is an end elevation, partly in section. Fig. 4 is a view similar to Fig. 3, illustrating a modified form of my invention. Fig. 5 is an end elevation of the clamping jaws, detached.

In the said drawings, A and A represent the two clamping jaws of the support, constructed of brass or other suitable alloy, and having fiat inner contact surfaces, the former provided witha dovetail groove, a, extending longitudinally of its inner face, and the latter provided with a corresponding dovetail projection, a, to engage and fit said groove. Each of said jaws is provided in the lower portion of its inner face with a groove, (tithe two grooves forming, when the jaws A A are united, an almost cylindrical conduit-in which the wire, 7, is clamped. These grooves (dare preferably somewhat less than semi circular in cross section, so as to embrace the wire from above to a point somewhat below its middle, leaving a portion of its lower face exposed, as shown, and as is usual in devices of this description. The upper portion of each jaw A A is provided with a semi-cylindrical shank, a threaded on its outer or curved surface, the two forming, when united, a threaded cylindrical shank. This shank is adapted to screw into a threaded socket, B, which is hinged by means of a pivot bolt or pin, 1), to a threaded shank, O, which screws into the insulator, D. The parts are assembled by placing the jaws A A' on opposite sides of the wire IV end to end, with said wire resting in the grooves and then sliding said jaws along the wire in opposite directions, the projection a engaging the groove a, and when the semi-shanks a are opposite each other, they are screwed into the socket B, thus locking the jaws from endwise motion, while the dovetail connection prevents lateral separation of the said jaws, thereby clamping the wire W firmly between said jaws.

It will be noted that the force preventing the separation of the jaws when properly en gaged is just as strong at the ends of said jaws as at the intermediate portions, from which it follows that the danger of the separation of the ends of the jaws hereinbefore pointed out as incident to the ordinary construction is entirely obviated, while at the same time the material most advantagv ous for preventing sparking may be employed in the construction of the clamp.

It will at once be obvious that my invention is in no wise limited to the particular means shown for connecting the wire clamping jaws with theirsupporting devices. The hinged construction shown is desirable, and is commonly employed in straight line work for the reason that it equalizes the strain on the jaws and therebytends to prevent wear. The jaws may, however, be screwed directly into the insulator, or otherwise supported. Moreover, although thethreaded shank and socket device shown and described form a desirable and convenient means for preventing longitudinal movement of the jaws relatively to each other when in place, yet I do not limit myself to this construction, as other means for effecting this result will readily suggest themselves, and in Fig. 4 I have shown a modification in which the threaded shanks on the jaws are dispensed with, said jaws being provided with unthreaded shanks, a, connected with a bifurcated shank, E, screwed into the insulator D by means of a pivot bolt, a which serves to prevent relative longitudinal movement of the jawsA A. Nor is my invention limited to the precise form of dovetail connection shown, since it is obvious that other forms of male and female connection may be substituted therefor, and the engaging device need not be continuous, as in the construction shown.

What I claim is- 1. The combination, with a wire to be supported, of clamping jaws adapted to engage and support said wire and respectively provided with a dovetail groove and corresponding projection extending the entire length thereof, and means for preventing relative longitudinal movement of the said jaws when in position, substantially as described.

2. The combination, with the jaws A A, having male and female connecting devices adapted to be engaged by relative longitudinal movement of said jaws, and each provided with a semi-cylindrical externally threaded shank, of a threaded socket to receive the said threaded shanks when in position, substantially as described.

3. The combination, with the jaws A A, adapted to clamp the wire, provided respectively with a dovetail groove a and corresponding projection to, and each having a semi-cylindrical externally threaded shank, of a correspondingly threaded socket to receive said threaded shanks, an insulator, and a shank secured to the insulator and pivoted to the socket, substantially as described.

4. The combination, with a wire to be supported, of clampingjaws provided with grooves forming a recess to receive the wire, said jaws having respectively a groove and a projection to engage therewith parallel with said recess, and means for holding said jaws in position with their said groove and projection in such engagement to prevent lateral separation of the jaws, substantially as described.

In testimony that I claim the foregoing as my invention I affix my signaturein presence of two witnesses.

A. IIELMER ENGLUND.

\Vitnesses:

IRVINE MILLER,

.IEORGE W. HIGGINS, J r. 

